The printing of textiles is currently accomplished primarily by rotary screen methods. In operation, screen printing is rapid and, for large runs, cost effective. However, cutting screens is expensive and time consuming thus making the per unit cost for short runs and strike-offs quite substantial and, in many cases, prohibitive.
A digital printing method such as ink jet printing offers a number of potential benefits over conventional screen printing methods. Digital printing eliminates the set up expense associated with screen preparation and can potentially enable cost effective short run production.
Ink jet printing furthermore allows visual effects such as tonal gradients and infinite pattern repeat size which can not be practically achieved by a screen printing process.
A disadvantage of ink jet printing, as it exists today, is relatively slow print speed. Current ink jet printers print at a rate of about 1-10 m2/hr max compared to a rate of greater than 1000 m2/hr for screen printing. To be competitive even for short runs, therefore, the speed of ink jet printers needs to be increased.
Another current disadvantage of ink jet printing is the limited amount of colorant and other solids an ink jet ink can contain. Ink jet printing cannot deliver the balance of vivid color as well as end use performance (durability) expected for production quality prints, particularly with pigmented inks. Also, pretreatment of textile fabrics has been required to get good color thus adding an additional step and cost to the manufacturing process. Prints on pretreated fabric may be more susceptible to pigment removal by abrasion and thus have reduced durability and wash fastness.
Yet another current disadvantage of ink jet printing is the limited number of inks which can be practically used on an ink jet printer at any one time. Screen printing can employ twenty or more (typically 10-13) mother colors which can provide a very wide gamut. Ink jet printers have traditionally been limited to no more than about six colors. Ink jet ink colors must thus be chosen judiciously in order to achieve a gamut similar to that of screen printing.